Duplication and familial promiscuity within the proteasome lid and COP9 signalosome kin complexes

Giovanna Serino, Elah Pick

Research output: Contribution to journalReview articlepeer-review


Two paralogous complexes, the proteasome lid and the COP9 signalosome (CSN), have diverged from a common ancestor; yet fulfill distinctive roles within the ubiquitin-proteasome sphere. The CSN regulates the largest family of E3 ubiquitin ligases, called CRLs (Cullin- RING ubiquitin Ligases), while the lid is a subcomplex of the 26. S proteasome, a proteolytic machinery responsible for the degradation of ubiquitinated proteins. Remarkably, in many organisms, several subunits of both complexes are duplicated, a circumstance that can hypothetically increase the number of different complexes that can be formed. Duplication, however, is not the only complexity trait within the lid and the CSN, because many of their subunits are not fully committed only to one of the two complexes, but they are able to associate with both. Indeed, their corresponding mutants have features that can be due to the absence of more than one complex. This could be simply explained by the subunits being able to carry an identical function within more than one paralogous complex or by the subunits having a certain level of promiscuity, i.e. being able to carry more than one function, depending on the complex they are associating with. Recent data show that both options are possible and, although their functional relevance still needs to be fully uncovered, evidence is accumulating, which indicates a promiscuous trading of paralogous subunits, and suggests that this may occur transiently, and/or in response to particular environmental conditions.

Original languageEnglish
Pages (from-to)89-97
Number of pages9
JournalPlant Science
StatePublished - Apr 2013

Bibliographical note

Funding Information:
This work was supported by a Institut Pasteur-Fondazione Cenci-Bolognetti grant 2009–2011 to G.S., by an Israel Science Foundation grant [ EP355/10 ] to E.P., and by a Ministry of Science and Technology (M.O.S.T)- Ministry of Foreign Affairs (MAE), Israel-Italy grant [ 3-9022 ] to G.S. and E.P.


  • Arabidopsis thaliana
  • COP9 signalosome
  • EIF3
  • PCI complexes
  • Proteasome lid
  • Saccharomyces cerevisiae

ASJC Scopus subject areas

  • Genetics
  • Agronomy and Crop Science
  • Plant Science


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